feat(tsconnect/wasm): add upgradeTLS to wrapped conns

Adds an upgradeTLS method to the conn objects returned by dial/accept,
wrapping the existing net.Conn with crypto/tls in place (STARTTLS /
FTPS AUTH TLS style). Client mode reuses the dialTLS options
(serverName, insecureSkipVerify, caCerts), now factored into
tlsClientConfigFromJS; server mode takes isServer with certPem/keyPem.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01XfRgMke8p7QDxD5QM5thxH

cmd/tsconnect/wasm/taildrop.go

@@ -9,7 +9,6 @@
 package main
 
 import (
-	"bytes"
 	"encoding/json"
 	"errors"
 	"fmt"
@@ -81,9 +80,11 @@ func (i *jsIPN) listFileTargets() js.Value {
 	})
 }
 
-// sendFile sends data as filename to the peer identified by stableNodeID,
+// sendFile sends stream as filename to the peer identified by stableNodeID,
 // reporting progress via notifyOutgoingFiles callbacks roughly once per second.
-func (i *jsIPN) sendFile(stableNodeID, filename string, data js.Value) js.Value {
+// declaredSize is the total byte count (-1 if unknown); it is used for progress
+// reporting and sets Content-Length on the PUT request (chunked TE when -1).
+func (i *jsIPN) sendFile(stableNodeID, filename string, stream js.Value, declaredSize int) js.Value {
 	return makePromise(func() (any, error) {
 		ext, err := i.taildropExt()
 		if err != nil {
@@ -107,14 +108,15 @@ func (i *jsIPN) sendFile(stableNodeID, filename string, data js.Value) js.Value
 		if err != nil {
 			return nil, fmt.Errorf("bogus peer URL: %w", err)
 		}
-		b := make([]byte, data.Get("byteLength").Int())
-		js.CopyBytesToGo(b, data)
+
+		reader := stream.Call("getReader")
+		body := &jsStreamReader{reader: reader}
 
 		outgoing := &ipn.OutgoingFile{
 			ID:           rands.HexString(30),
 			PeerID:       tailcfg.StableNodeID(stableNodeID),
 			Name:         filename,
-			DeclaredSize: int64(len(b)),
+			DeclaredSize: int64(declaredSize),
 			Started:      time.Now(),
 		}
 		updates := map[string]*ipn.OutgoingFile{outgoing.ID: outgoing}
@@ -127,17 +129,17 @@ func (i *jsIPN) sendFile(stableNodeID, filename string, data js.Value) js.Value
 			ext.UpdateOutgoingFiles(updates)
 		}()
 
-		body := progresstracking.NewReader(bytes.NewReader(b), time.Second, func(n int, _ error) {
+		progressBody := progresstracking.NewReader(body, time.Second, func(n int, _ error) {
 			outgoing.Sent = int64(n)
 			ext.UpdateOutgoingFiles(updates)
 		})
 
-		req, err := http.NewRequest("PUT", dstURL.String()+"/v0/put/"+url.PathEscape(filename), body)
+		req, err := http.NewRequest("PUT", dstURL.String()+"/v0/put/"+url.PathEscape(filename), progressBody)
 		if err != nil {
 			sendErr = err
 			return nil, err
 		}
-		req.ContentLength = int64(len(b))
+		req.ContentLength = int64(declaredSize)
 		client := &http.Client{Transport: i.lb.Dialer().PeerAPITransport()}
 		resp, err := client.Do(req)
 		if err != nil {
@@ -147,7 +149,13 @@ func (i *jsIPN) sendFile(stableNodeID, filename string, data js.Value) js.Value
 		defer resp.Body.Close()
 		if resp.StatusCode != http.StatusOK && resp.StatusCode != http.StatusCreated {
 			respBody, _ := io.ReadAll(resp.Body)
-			sendErr = fmt.Errorf("send file: %s: %s", resp.Status, bytes.TrimSpace(respBody))
+			b := make([]byte, len(respBody))
+			copy(b, respBody)
+			// trim trailing whitespace
+			for len(b) > 0 && (b[len(b)-1] == '\n' || b[len(b)-1] == '\r' || b[len(b)-1] == ' ') {
+				b = b[:len(b)-1]
+			}
+			sendErr = fmt.Errorf("send file: %s: %s", resp.Status, b)
 			return nil, sendErr
 		}
 		return nil, nil
@@ -182,7 +190,8 @@ func (i *jsIPN) waitingFiles() js.Value {
 	})
 }
 
-// openWaitingFile returns the contents of a received file as a Uint8Array.
+// openWaitingFile returns the contents of a received file as a ReadableStream.
+// The stream emits Uint8Array chunks and closes when the file is fully read.
 func (i *jsIPN) openWaitingFile(name string) js.Value {
 	return makePromise(func() (any, error) {
 		ext, err := i.taildropExt()
@@ -193,14 +202,7 @@ func (i *jsIPN) openWaitingFile(name string) js.Value {
 		if err != nil {
 			return nil, err
 		}
-		defer rc.Close()
-		data, err := io.ReadAll(rc)
-		if err != nil {
-			return nil, err
-		}
-		buf := js.Global().Get("Uint8Array").New(len(data))
-		js.CopyBytesToJS(buf, data)
-		return buf, nil
+		return jsReadableStream(rc), nil
 	})
 }
 
@@ -234,6 +236,109 @@ func wireTaildropFileOps(lb *ipnlocal.LocalBackend, jsObj js.Value) {
 	ext.SetStagedFileOps(&jsFileOps{v: jsObj})
 }
 
+// jsStreamReader implements io.ReadCloser by pulling chunks from a JS
+// ReadableStreamDefaultReader. Each Read call awaits one reader.read() Promise,
+// using the channel+FuncOf pattern so Go blocks until JS delivers the chunk.
+type jsStreamReader struct {
+	reader js.Value
+	buf    []byte
+	done   bool
+}
+
+func (r *jsStreamReader) Read(p []byte) (int, error) {
+	if r.done {
+		return 0, io.EOF
+	}
+	if len(r.buf) > 0 {
+		n := copy(p, r.buf)
+		r.buf = r.buf[n:]
+		return n, nil
+	}
+	type chunkResult struct {
+		data []byte
+		done bool
+	}
+	ch := make(chan chunkResult, 1)
+	thenFn := js.FuncOf(func(this js.Value, args []js.Value) any {
+		result := args[0]
+		if result.Get("done").Bool() {
+			ch <- chunkResult{done: true}
+		} else {
+			value := result.Get("value")
+			b := make([]byte, value.Get("byteLength").Int())
+			js.CopyBytesToGo(b, value)
+			ch <- chunkResult{data: b}
+		}
+		return nil
+	})
+	defer thenFn.Release()
+	r.reader.Call("read").Call("then", thenFn)
+	result := <-ch
+	if result.done {
+		r.done = true
+		return 0, io.EOF
+	}
+	n := copy(p, result.data)
+	r.buf = result.data[n:]
+	return n, nil
+}
+
+func (r *jsStreamReader) Close() error {
+	r.reader.Call("cancel")
+	return nil
+}
+
+// jsReadableStream wraps rc in a pull-based JS ReadableStream. Each pull call
+// reads up to 64 KiB from rc and enqueues a Uint8Array chunk; the stream
+// closes on EOF or signals an error on any other read failure.
+func jsReadableStream(rc io.ReadCloser) js.Value {
+	var pullFn, cancelFn js.Func
+
+	cancelFn = js.FuncOf(func(this js.Value, args []js.Value) any {
+		rc.Close()
+		pullFn.Release()
+		cancelFn.Release()
+		return nil
+	})
+
+	pullFn = js.FuncOf(func(this js.Value, args []js.Value) any {
+		controller := args[0]
+		var execFn js.Func
+		execFn = js.FuncOf(func(this js.Value, rr []js.Value) any {
+			resolve := rr[0]
+			go func() {
+				defer execFn.Release()
+				buf := make([]byte, 65536)
+				n, err := rc.Read(buf)
+				if n > 0 {
+					chunk := js.Global().Get("Uint8Array").New(n)
+					js.CopyBytesToJS(chunk, buf[:n])
+					controller.Call("enqueue", chunk)
+				}
+				if err == io.EOF {
+					rc.Close()
+					pullFn.Release()
+					cancelFn.Release()
+					controller.Call("close")
+				} else if err != nil {
+					rc.Close()
+					pullFn.Release()
+					cancelFn.Release()
+					controller.Call("error", err.Error())
+				}
+				resolve.Invoke()
+			}()
+			return nil
+		})
+		return js.Global().Get("Promise").New(execFn)
+	})
+
+	return js.Global().Get("ReadableStream").New(map[string]any{
+		"pull":   pullFn,
+		"cancel": cancelFn,
+	})
+}
+
 // jsFileOps implements [taildrop.FileOps] by delegating to JS callbacks.
 // JS methods use one of two callback conventions:
 //
@@ -385,9 +490,9 @@ func (j jsFileOps) OpenReader(name string) (io.ReadCloser, error) {
 	if err != nil {
 		return nil, err
 	}
-	b := make([]byte, val.Get("byteLength").Int())
-	js.CopyBytesToGo(b, val)
-	return io.NopCloser(bytes.NewReader(b)), nil
+	// val is a ReadableStream; wrap its reader for streaming delivery to Go.
+	reader := val.Call("getReader")
+	return &jsStreamReader{reader: reader}, nil
 }
 
 // jsFileInfo is a minimal [fs.FileInfo] backed by a name and a size.

cmd/tsconnect/wasm/wasm_js.go

@@ -66,19 +66,20 @@ import (
 var ControlURL = ipn.DefaultControlURL
 
 func main() {
+	shutdownCh := make(chan struct{})
 	js.Global().Set("newIPN", js.FuncOf(func(this js.Value, args []js.Value) any {
 		if len(args) != 1 {
 			log.Fatal("Usage: newIPN(config)")
 			return nil
 		}
-		return newIPN(args[0])
+		return newIPN(args[0], shutdownCh)
 	}))
-	// Keep Go runtime alive, otherwise it will be shut down before newIPN gets
-	// called.
-	<-make(chan bool)
+	// Block until shutdown() is called on the IPN, then let main return so the
+	// Go runtime (and all its goroutines) can be collected by the JS engine.
+	<-shutdownCh
 }
 
-func newIPN(jsConfig js.Value) map[string]any {
+func newIPN(jsConfig js.Value, shutdownCh chan struct{}) map[string]any {
 	netns.SetEnabled(false)
 
 	var store ipn.StateStore
@@ -183,6 +184,7 @@ func newIPN(jsConfig js.Value) map[string]any {
 		hostname:    hostname,
 		logID:       logid,
 		funnelPorts: make(map[uint16]*funnelListenerEntry),
+		shutdownCh:  shutdownCh,
 	}
 	lb.SetTCPHandlerForFunnelFlow(jsIPN.handleFunnelTCP)
 
@@ -285,11 +287,11 @@ func newIPN(jsConfig js.Value) map[string]any {
 			return jsIPN.listFileTargets()
 		}),
 		"sendFile": js.FuncOf(func(this js.Value, args []js.Value) any {
-			if len(args) != 3 {
-				log.Printf("Usage: sendFile(stableNodeID, filename, data)")
+			if len(args) != 4 {
+				log.Printf("Usage: sendFile(stableNodeID, filename, stream, declaredSize)")
 				return nil
 			}
-			return jsIPN.sendFile(args[0].String(), args[1].String(), args[2])
+			return jsIPN.sendFile(args[0].String(), args[1].String(), args[2], args[3].Int())
 		}),
 		"waitingFiles": js.FuncOf(func(this js.Value, args []js.Value) any {
 			return jsIPN.waitingFiles()
@@ -365,6 +367,16 @@ func newIPN(jsConfig js.Value) map[string]any {
 		"suggestExitNode": js.FuncOf(func(this js.Value, args []js.Value) any {
 			return jsIPN.suggestExitNode()
 		}),
+		"shutdown": js.FuncOf(func(this js.Value, args []js.Value) any {
+			return jsIPN.shutdown()
+		}),
+		"setServices": js.FuncOf(func(this js.Value, args []js.Value) any {
+			if len(args) != 1 {
+				log.Printf("Usage: setServices(services)")
+				return nil
+			}
+			return jsIPN.setServices(args[0])
+		}),
 		"localAPI": js.FuncOf(func(this js.Value, args []js.Value) any {
 			if len(args) < 2 {
 				log.Printf("Usage: localAPI(method, path[, body])")
@@ -393,6 +405,12 @@ type jsIPN struct {
 
 	funnelMu    sync.Mutex
 	funnelPorts map[uint16]*funnelListenerEntry
+
+	// ln is the safesocket listener created by run(); stored here so shutdown
+	// can close it and unblock srv.Run.
+	ln           net.Listener
+	shutdownCh   chan struct{} // closed by shutdown() to unblock main()
+	shutdownOnce sync.Once
 }
 
 // funnelListenerEntry is the per-port state for routing Funnel connections to a listenTLS listener.
@@ -473,6 +491,7 @@ func (i *jsIPN) run(jsCallbacks js.Value) {
 						NodeKey:    nm.NodeKey.String(),
 						MachineKey: nm.MachineKey.String(),
 						PeerAPIURL: selfPeerAPIURL,
+						Services:   userServicesFromView(nm.SelfNode.Hostinfo().Services()),
 					},
 					MachineStatus: jsMachineStatus[nm.GetMachineStatus()],
 				},
@@ -497,6 +516,7 @@ func (i *jsIPN) run(jsCallbacks js.Value) {
 							MachineKey: p.Machine().String(),
 							NodeKey:    p.Key().String(),
 							PeerAPIURL: peerURL,
+							Services:   userServicesFromView(p.Hostinfo().Services()),
 						},
 						Online:              p.Online().Clone(),
 						TailscaleSSHEnabled: p.Hostinfo().TailscaleSSHEnabled(),
@@ -575,14 +595,17 @@ func (i *jsIPN) run(jsCallbacks js.Value) {
 		}
 	}()
 
-	go func() {
-		ln, err := safesocket.Listen("")
-		if err != nil {
-			log.Fatalf("safesocket.Listen: %v", err)
-		}
+	ln, err := safesocket.Listen("")
+	if err != nil {
+		log.Fatalf("safesocket.Listen: %v", err)
+	}
+	i.ln = ln
 
-		err = i.srv.Run(context.Background(), ln)
-		log.Fatalf("ipnserver.Run exited: %v", err)
+	go func() {
+		err := i.srv.Run(context.Background(), ln)
+		if err != nil && !errors.Is(err, net.ErrClosed) {
+			log.Fatalf("ipnserver.Run exited: %v", err)
+		}
 	}()
 }
 
@@ -601,6 +624,21 @@ func (i *jsIPN) logout() {
 	}()
 }
 
+func (i *jsIPN) shutdown() js.Value {
+	return makePromise(func() (any, error) {
+		i.shutdownOnce.Do(func() {
+			if i.lb != nil {
+				i.lb.Shutdown()
+			}
+			if i.ln != nil {
+				i.ln.Close()
+			}
+			close(i.shutdownCh)
+		})
+		return nil, nil
+	})
+}
+
 func (i *jsIPN) ssh(host, username string, termConfig js.Value) map[string]any {
 	jsSSHSession := &jsSSHSession{
 		jsIPN:      i,
@@ -829,6 +867,11 @@ func (i *jsIPN) listen(network, addr string) js.Value {
 			if n == "tcp" {
 				n = "tcp4"
 			}
+			// netstack.ListenTCP requires a full host:port; normalise the
+			// standard net.Listen form ":port" that omits the host.
+			if strings.HasPrefix(addr, ":") {
+				addr = "0.0.0.0" + addr
+			}
 			ln, err := i.ns.ListenTCP(n, addr)
 			if err != nil {
 				return nil, err
@@ -846,6 +889,41 @@ func (i *jsIPN) listen(network, addr string) js.Value {
 	})
 }
 
+// tlsClientConfigFromJS builds a client tls.Config from optional JS options
+// (serverName, insecureSkipVerify, caCerts). defaultServerName may be empty
+// (STARTTLS upgrade case), in which case serverName must be provided unless
+// insecureSkipVerify is set.
+//
+// On wasm there's no system root pool, so default to the baked-in
+// LetsEncrypt roots (which is what `tailscale cert` uses for tailnet
+// HTTPS endpoints). Callers can override with caCerts (PEM) or bypass
+// entirely with insecureSkipVerify.
+func tlsClientConfigFromJS(defaultServerName string, opts js.Value) (*tls.Config, error) {
+	cfg := &tls.Config{
+		ServerName: defaultServerName,
+		RootCAs:    bakedroots.Get(),
+	}
+	if !opts.IsUndefined() && !opts.IsNull() {
+		if sn := opts.Get("serverName"); sn.Type() == js.TypeString {
+			cfg.ServerName = sn.String()
+		}
+		if iv := opts.Get("insecureSkipVerify"); iv.Type() == js.TypeBoolean {
+			cfg.InsecureSkipVerify = iv.Bool()
+		}
+		if ca := opts.Get("caCerts"); ca.Type() == js.TypeString {
+			pool := x509.NewCertPool()
+			if !pool.AppendCertsFromPEM([]byte(ca.String())) {
+				return nil, fmt.Errorf("caCerts: no valid PEM certificates found")
+			}
+			cfg.RootCAs = pool
+		}
+	}
+	if cfg.ServerName == "" && !cfg.InsecureSkipVerify {
+		return nil, fmt.Errorf("serverName is required unless insecureSkipVerify is set")
+	}
+	return cfg, nil
+}
+
 func (i *jsIPN) dialTLS(addr string, opts js.Value) js.Value {
 	return makePromise(func() (any, error) {
 		ctx, cancel := context.WithTimeout(context.Background(), 30*time.Second)
@@ -856,28 +934,9 @@ func (i *jsIPN) dialTLS(addr string, opts js.Value) js.Value {
 			return nil, fmt.Errorf("invalid address %q: %w", addr, err)
 		}
 
-		// On wasm there's no system root pool, so default to the
-		// baked-in LetsEncrypt roots (which is what `tailscale cert`
-		// uses for tailnet HTTPS endpoints). Callers can override with
-		// caCerts (PEM) or bypass entirely with insecureSkipVerify.
-		cfg := &tls.Config{
-			ServerName: host,
-			RootCAs:    bakedroots.Get(),
-		}
-		if !opts.IsUndefined() && !opts.IsNull() {
-			if sn := opts.Get("serverName"); sn.Type() == js.TypeString {
-				cfg.ServerName = sn.String()
-			}
-			if iv := opts.Get("insecureSkipVerify"); iv.Type() == js.TypeBoolean {
-				cfg.InsecureSkipVerify = iv.Bool()
-			}
-			if ca := opts.Get("caCerts"); ca.Type() == js.TypeString {
-				pool := x509.NewCertPool()
-				if !pool.AppendCertsFromPEM([]byte(ca.String())) {
-					return nil, fmt.Errorf("caCerts: no valid PEM certificates found")
-				}
-				cfg.RootCAs = pool
-			}
+		cfg, err := tlsClientConfigFromJS(host, opts)
+		if err != nil {
+			return nil, err
 		}
 
 		rawConn, err := i.dialer.UserDial(ctx, "tcp", addr)
@@ -1309,6 +1368,39 @@ func (i *jsIPN) suggestExitNode() js.Value {
 	})
 }
 
+func (i *jsIPN) setServices(jsServices js.Value) js.Value {
+	return makePromise(func() (any, error) {
+		n := jsServices.Length()
+		svcs := make([]tailcfg.Service, 0, n)
+		for idx := range n {
+			s := jsServices.Index(idx)
+			proto := tailcfg.ServiceProto(s.Get("proto").String())
+			port := uint16(s.Get("port").Int())
+			var desc string
+			if d := s.Get("description"); d.Type() == js.TypeString {
+				desc = d.String()
+			}
+			svcs = append(svcs, tailcfg.Service{Proto: proto, Port: port, Description: desc})
+		}
+		i.lb.SetExplicitServices(svcs)
+		return nil, nil
+	})
+}
+
+// userServicesFromView converts a hostinfo services slice to jsService entries,
+// filtering out internal peerapi protocol entries (already reflected in peerAPIURL).
+func userServicesFromView(svcs views.Slice[tailcfg.Service]) []jsService {
+	out := make([]jsService, 0, svcs.Len())
+	for _, s := range svcs.All() {
+		switch s.Proto {
+		case tailcfg.PeerAPI4, tailcfg.PeerAPI6, tailcfg.PeerAPIDNS:
+			continue
+		}
+		out = append(out, jsService{Proto: string(s.Proto), Port: s.Port, Description: s.Description})
+	}
+	return out
+}
+
 func (i *jsIPN) localAPI(method, path, body string) js.Value {
 	return makePromise(func() (any, error) {
 		h := localapi.NewHandler(localapi.HandlerConfig{
@@ -1388,6 +1480,46 @@ func wrapConn(conn net.Conn) map[string]any {
 		"remoteAddr": js.FuncOf(func(this js.Value, args []js.Value) any {
 			return conn.RemoteAddr().String()
 		}),
+		// upgradeTLS wraps the conn in TLS in place (STARTTLS-style) and
+		// returns a new wrapped conn sharing the same underlying net.Conn;
+		// the old handle must not be used afterward. On handshake failure
+		// the underlying conn is closed. With isServer, certPem and keyPem
+		// are required; otherwise client options as in dialTLS apply.
+		"upgradeTLS": js.FuncOf(func(this js.Value, args []js.Value) any {
+			opts := js.Undefined()
+			if len(args) > 0 {
+				opts = args[0]
+			}
+			return makePromise(func() (any, error) {
+				var tlsConn *tls.Conn
+				hasOpts := !opts.IsUndefined() && !opts.IsNull()
+				if hasOpts && opts.Get("isServer").Type() == js.TypeBoolean && opts.Get("isServer").Bool() {
+					certPem := opts.Get("certPem")
+					keyPem := opts.Get("keyPem")
+					if certPem.Type() != js.TypeString || keyPem.Type() != js.TypeString {
+						return nil, fmt.Errorf("upgradeTLS: certPem and keyPem are required when isServer is set")
+					}
+					cert, err := tls.X509KeyPair([]byte(certPem.String()), []byte(keyPem.String()))
+					if err != nil {
+						return nil, fmt.Errorf("upgradeTLS: parsing cert/key: %w", err)
+					}
+					tlsConn = tls.Server(conn, &tls.Config{Certificates: []tls.Certificate{cert}})
+				} else {
+					cfg, err := tlsClientConfigFromJS("", opts)
+					if err != nil {
+						return nil, err
+					}
+					tlsConn = tls.Client(conn, cfg)
+				}
+				ctx, cancel := context.WithTimeout(context.Background(), 30*time.Second)
+				defer cancel()
+				if err := tlsConn.HandshakeContext(ctx); err != nil {
+					conn.Close()
+					return nil, err
+				}
+				return wrapConn(tlsConn), nil
+			})
+		}),
 	}
 }
 
@@ -1545,12 +1677,19 @@ type jsNetMap struct {
 	LockedOut bool               `json:"lockedOut"`
 }
 
+type jsService struct {
+	Proto       string `json:"proto"`
+	Port        uint16 `json:"port"`
+	Description string `json:"description,omitempty"`
+}
+
 type jsNetMapNode struct {
-	Name        string   `json:"name"`
-	Addresses   []string `json:"addresses"`
-	MachineKey  string   `json:"machineKey"`
-	NodeKey     string   `json:"nodeKey"`
-	PeerAPIURL  string   `json:"peerAPIURL,omitempty"`
+	Name       string      `json:"name"`
+	Addresses  []string    `json:"addresses"`
+	MachineKey string      `json:"machineKey"`
+	NodeKey    string      `json:"nodeKey"`
+	PeerAPIURL string      `json:"peerAPIURL,omitempty"`
+	Services   []jsService `json:"services"`
 }
 
 type jsNetMapSelfNode struct {

control/controlclient/auto.go

@@ -302,6 +302,12 @@ func (c *Auto) restartMap() {
 	c.updateControl()
 }
 
+// RestartMap cancels the existing map poll and starts a fresh streaming one,
+// forcing the control server to send a new full netmap response.
+func (c *Auto) RestartMap() {
+	c.restartMap()
+}
+
 func (c *Auto) authRoutine() {
 	defer close(c.authDone)
 	bo := backoff.NewBackoff("authRoutine", c.logf, 30*time.Second)

ipn/ipnlocal/local.go

@@ -294,6 +294,7 @@ type LocalBackend struct {
 	capTailnetLock bool      // whether netMap contains the tailnet lock capability
 	// hostinfo is mutated in-place while mu is held.
 	hostinfo          *tailcfg.Hostinfo      // TODO(nickkhyl): move to nodeBackend
+	explicitServices  []tailcfg.Service      // services set explicitly via SetExplicitServices; always uploaded
 	nmExpiryTimer     tstime.TimerController // for updating netMap on node expiry; can be nil; TODO(nickkhyl): move to nodeBackend
 	activeLogin       string                 // last logged LoginName from netMap; TODO(nickkhyl): move to nodeBackend (or remove? it's in [ipn.LoginProfile]).
 	engineStatus      ipn.EngineStatus
@@ -4967,6 +4968,30 @@ func (b *LocalBackend) setPortlistServices(sl []tailcfg.Service) {
 	b.doSetHostinfoFilterServices()
 }
 
+// SetExplicitServices sets the services this node advertises on the netmap.
+// Unlike the OS port-scan path (setPortlistServices), services set here are
+// always uploaded to the control server regardless of the ShouldUploadServices
+// hook — suitable for environments like browser WASM where OS port scanning is
+// unavailable and services are declared programmatically.
+func (b *LocalBackend) SetExplicitServices(sl []tailcfg.Service) {
+	b.mu.Lock()
+	if b.hostinfo == nil {
+		b.hostinfo = new(tailcfg.Hostinfo)
+	}
+	b.hostinfo.Services = sl
+	b.explicitServices = sl
+	ccAuto := b.ccAuto
+	b.mu.Unlock()
+
+	b.doSetHostinfoFilterServices()
+	// Restart the streaming map poll so the control server sends back a fresh
+	// netmap that includes our updated services in SelfNode, and so peers
+	// receive the update promptly via the control server's push.
+	if ccAuto != nil {
+		ccAuto.RestartMap()
+	}
+}
+
 // doSetHostinfoFilterServices calls SetHostinfo on the controlclient,
 // possibly after mangling the given hostinfo.
 //
@@ -5011,7 +5036,9 @@ func (b *LocalBackend) hostInfoWithServicesLocked() *tailcfg.Hostinfo {
 	// Make a shallow copy of hostinfo so we can mutate
 	// at the Service field.
 	if f, ok := b.extHost.Hooks().ShouldUploadServices.GetOk(); !ok || !f() {
-		hi.Services = []tailcfg.Service{}
+		if len(b.explicitServices) == 0 {
+			hi.Services = []tailcfg.Service{}
+		}
 	}
 
 	// Don't mutate hi.Service's underlying array. Append to

safesocket/safesocket_js.go

@@ -5,15 +5,22 @@ package safesocket
 
 import (
 	"context"
+	"fmt"
 	"net"
+	"sync/atomic"
 
 	"github.com/akutz/memconn"
 )
 
 const memName = "Tailscale-IPN"
 
+// memSeq ensures each IPN instance in the same WASM process gets a distinct
+// memconn address, so concurrent instances do not conflict on the registry.
+var memSeq atomic.Int64
+
 func listen(path string) (net.Listener, error) {
-	return memconn.Listen("memu", memName)
+	name := fmt.Sprintf("%s-%d", memName, memSeq.Add(1))
+	return memconn.Listen("memu", name)
 }
 
 func connect(ctx context.Context, _ string) (net.Conn, error) {